Hose clamps have been designed in a great variety of forms which fall into three general types. A first of these types is a continuous band which includes an upstanding portion or "ear" which can be deformed after assembly to tension the band around a hose. Such clamps are sometimes referred to as "Oetiker" clamps after the inventor. The clamps are engaged on a hose by using a special tool to deform the ear and thereby tension the band to apply a compressive radial stress on the hose.
A second type of clamp includes a mechanical actuator, such as a worm screw, acting directly on a band to bring the band into firm engagement with the hose. Lastly, the third type is a clamp of spring steel made to have a diameter slightly less than that of the outside diameter of the hose. As a result, when the clamp is pre-loaded by deforming it to enlarge the clamp, there will be stored energy in the clamp which can be released to apply a compressive radial force to hold the clamp on the hose.
A variation to the pre-loaded type is a clamp made of spring steel; and shaped to be enlarged into an open position at the point of manufacture to store energy. The clamp is retained in this open condition either by built-in structure or by a keeper in the form of a clip. In use the clamp is released over the hose to clamp the hose.
It has become common practice to pre-assemble clamps on a hose and provide this assembly to the automobile assembly line. The clamps are typically placed on the hose and either glued in position at a point diametrically opposite the restraining structure or held in place by a clamp retention device which engages the hose to hold the clamp in place. The clamp is then in place to be released closed into a condition to apply a radial compressive load on the hose.
Examples of such clamp retention devices are found in U.S. Pat. Ser. Nos. 4,882,814 and 5,234,233. Typically, such structures are arranged about the clamp at the location of the clamp on the hose. Consequently, when the hose is pushed on to a rigid tubular fitting the hose must be free to expand slightly and this expansion can be impeded by the mechanical structure. This is because the structure usually applies some form of radial compression on the tube in order to hold the structure, and hence the clamp, in place on the hose.
Accordingly, it is one of the objects of the present invention to minimize the effect of a clamp retaining structure on the normal procedure for placing an prestressed open clamp on a hose and then engaging the hose on a rigid tubular fitting.